The present invention concerns novel derivatives of thiadiazole compounds. More particularly, the novel thiadiazoles are derived from a polyolefin and 1,3,4-thiadiazole compound. The invention further concerns improved lubricating compositions containing said thiadiazole derivatives.
During normal operation of internal combustion engines, oil-insoluble sludge forms in the crankcase and oil passages of a gasoline or diesel engine. Sludge affects the ability of the lubricating oil to effectively lubricate the engine parts and, by entrapment of water, contributes to rust formation in the engine.
To prevent sludge formation on the engine, dispersants or detergents are added to the lubricating formulation. The additives maintain sludge particles suspended in the oil and thus minimize deposits on the engine surfaces and on the oil filter.
Known detergents or dispersants are either metal salts or of the ashless type. Due to environmental considerations, ashless dispersants are preferred. For economical reasons, it is also preferred that the additive possesses other functional properties for improving the lubricating properties of the oil.
It has been surprisingly discovered that certain polyalkylated 1,3,4-thiadiazoles possess dispersant as well as antiwear and antioxidant properties.
In prior art, lower chain alkyl derivatives of 2,5-disulfinyl-1,3,4-thiadiazoles have been disclosed as surfactants in U.S. Pat. No. 4,432,847.